rds: tcp: atomically purge entries from rds_tcp_conn_list during netns delete
commit f10b4cff98
upstream.
The rds_tcp_kill_sock() function parses the rds_tcp_conn_list
to find the rds_connection entries marked for deletion as part
of the netns deletion under the protection of the rds_tcp_conn_lock.
Since the rds_tcp_conn_list tracks rds_tcp_connections (which
have a 1:1 mapping with rds_conn_path), multiple tc entries in
the rds_tcp_conn_list will map to a single rds_connection, and will
be deleted as part of the rds_conn_destroy() operation that is
done outside the rds_tcp_conn_lock.
The rds_tcp_conn_list traversal done under the protection of
rds_tcp_conn_lock should not leave any doomed tc entries in
the list after the rds_tcp_conn_lock is released, else another
concurrently executiong netns delete (for a differnt netns) thread
may trip on these entries.
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
c64534f826
commit
83ee02de2c
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@ -306,7 +306,8 @@ static void rds_tcp_conn_free(void *arg)
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rdsdebug("freeing tc %p\n", tc);
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rdsdebug("freeing tc %p\n", tc);
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spin_lock_irqsave(&rds_tcp_conn_lock, flags);
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spin_lock_irqsave(&rds_tcp_conn_lock, flags);
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list_del(&tc->t_tcp_node);
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if (!tc->t_tcp_node_detached)
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list_del(&tc->t_tcp_node);
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spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
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spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
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kmem_cache_free(rds_tcp_conn_slab, tc);
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kmem_cache_free(rds_tcp_conn_slab, tc);
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@ -531,8 +532,12 @@ static void rds_tcp_kill_sock(struct net *net)
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if (net != c_net || !tc->t_sock)
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if (net != c_net || !tc->t_sock)
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continue;
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continue;
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if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
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if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
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list_move_tail(&tc->t_tcp_node, &tmp_list);
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list_move_tail(&tc->t_tcp_node, &tmp_list);
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} else {
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list_del(&tc->t_tcp_node);
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tc->t_tcp_node_detached = true;
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}
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}
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}
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spin_unlock_irq(&rds_tcp_conn_lock);
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spin_unlock_irq(&rds_tcp_conn_lock);
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list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
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list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
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@ -12,6 +12,7 @@ struct rds_tcp_incoming {
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struct rds_tcp_connection {
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struct rds_tcp_connection {
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struct list_head t_tcp_node;
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struct list_head t_tcp_node;
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bool t_tcp_node_detached;
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struct rds_conn_path *t_cpath;
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struct rds_conn_path *t_cpath;
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/* t_conn_path_lock synchronizes the connection establishment between
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/* t_conn_path_lock synchronizes the connection establishment between
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* rds_tcp_accept_one and rds_tcp_conn_path_connect
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* rds_tcp_accept_one and rds_tcp_conn_path_connect
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